1. Field of the Invention
The invention relates to a piezoelectric crystal driver device, and more particularly to a pulse rate modulation type method and driver device for driving a piezoelectric crystal.
2. Description of the Related Art
Piezoelectric crystals are widely used in microphones, loudspeakers, sound pick-up devices, buzzers, etc. The piezoelectric crystal expands or bends whenever a signal voltage is applied thereto. This deflection results in the generation of an appropriate sound output.
The conventional method used in driving piezoelectric crystals is as follows: A digitized sound signal input (such as speech, music, etc.) is converted into an appropriate analog signal via a digital-to-analog converter means. The analog signal is then applied onto the terminals of the piezoelectric crystal, causing the piezoelectric crystal to vibrate and thereby produce sound.